4MA0 Higher June 2017 Paper 3 Q10
10 Solve the simultaneous equations
\[\begin{aligned} 2x + 7y &= 31 \\ 5x - 3y &= 16 \end{aligned}\]Show clear algebraic working.
(4)
| Scheme | Marks |
|---|---|
| Eg \(10x + 35y = 155\) \(-\;\;10x - 6y = 32\) or \(6x + 21y = 93\) \(+\;\;35x - 21y = 112\) | M1 |
| A1 | |
| M1 | |
| \(x = 5\), \(y = 3\) | A1 |
| (4) | |
| (4 marks) |
Notes
M1: for coefficient of \(x\) or \(y\) the same and correct operation to eliminate selected variable (condone any one arithmetic error in multiplication) or
for correct rearrangement of one equation followed by correct substitution in the other.
A1: cao (dep on M1)
M1: (dep on 1st M1) for substituting their found value into one of the equations
or
correct method of elimination to find the second variable (as for first M1)
A1: cao
Award 4 marks for correct values if at least first M1 scored